Hello everyone, perhaps someone here can help me. I keep my streaming audio files on an external HD. When I tried to look at what I have in there (checking the available space cuz I just bought IK percussion on 50% sales using my credits) it shows I have 163G free out of 465G but there's nothing in there! Windows says "The folder is empty". So I load up Treesize Pro (a wonderfully great file management utility) and it shows, folders for XLN Audio, Garritan, Cakewalk Sample Data, IK Multimedia, NI, etc but all the folders are marked with an error saying "The system cannot fine the file specified." Size = 0. Allocated = 0. Files = 0. Last change = 3/16/2016 (which is correct). What happened? How can I get these files back? I figure they're still there but the pointers messed up somehow. Thanks for any ideas offered.

I had an external USB drive that messed up once.  I must have forgotten to eject it first or something, and that probably boogered up the partition.
 
I ran this free partition recovery utility, and got my partition back! 
http://www.easeus.com/partition-recovery/index.htm
 
They also have a free file recovery utility as well.

STOP
The first principle in a situation like this is to be sure nothing you do is writing to the drive in question. Ideally, you would do a sector by sector raw (forensic) copy of the drive to another location and disconnect the bad drive before trying to do troubleshooting on the copy. The usual imaging or backup solutions will not work, as they do not copy "empty" space. If that is impractical, and the files are not critical, you can try to use data recovery software, if you have a large enough disk to store recovered files. You can generally find a download on the website of the disk drive manufacturer that will test the physical integrity of the disk, just avoid the test versions that are destructive or surface tests. If the disk is intact, then likely you have lost the file system through corruption. It is tempting to use a repair that just restores the damaged file system, but that risks further data loss if it fails. Running CHKDSK without the /R (repair) switch on the bad drive is generally safe and may provide additional information about the problem. Windows is very bad at recovering fragmented files, but there are a bunch of good free file recovery programs that can do a good job, but they will require hours to do it. It will also require hours of reading of their manuals to understand what they are going to do. 
https://fossbytes.com/top-best-free-data-recovery-software-2016/
 

Since this is a streaming sample drive and not an OS drive, there is a low chance of Windows writing to it.  Agree that not using it until testing and recovery is complete is very good advice!
 
There are some good file recovery products in that list.  I have used the first one, Recuva, which is the editor's choice, as well as Puran File Recovery.  I like them both.  If you follow directions provided, most will inform you to save any recovered files to a new location.
 
I would probably stick to the file recovery tools if I just needed to recover some deleted files, and would try that first, after a CHKDSK.  But if that does not work and if the partition is hosed, I would try EaseUS.  The EaseUS Partition recovery is the only tool that allowed me to recover a corrupted partition.